Algorithmic and Hardness Results for the Colorful Components Problems

In this paper we investigate the colorful components framework, motivated by applications emerging from comparative genomics. The general goal is to remove a collection of edges from an undirected vertex-colored graph $G$ such that in the resulting graph $G'$ all the connected components are colorful (i.e., any two vertices of the same color belong to different connected components). We want $G'$ to optimize an objective function, the selection of this function being specific to each problem in the framework. We analyze three objective functions, and thus, three different problems, which are believed to be relevant for the biological applications: minimizing the number of singleton vertices, maximizing the number of edges in the transitive closure, and minimizing the number of connected components. Our main result is a polynomial time algorithm for the first problem. This result disproves the conjecture of Zheng et al. that the problem is $NP$-hard (assuming $P \neq NP$). Then, we show that the second problem is $APX$-hard, thus proving and strengthening the conjecture of Zheng et al. that the problem is $NP$-hard. Finally, we show that the third problem does not admit polynomial time approximation within a factor of $|V|^{1/14 - \epsilon}$ for any $\epsilon > 0$, assuming $P \neq NP$ (or within a factor of $|V|^{1/2 - \epsilon}$, assuming $ZPP \neq NP$).Comment: 18 pages, 3 figure

KNOWING, LOVING, AND BEING THROUGH EXCESS: CREATION OF SUBJECT IN BERTHA HARRIS’S LOVER

This article is a psychoanalytic and feminist reading of Bertha Harris’s novel Lover, a text that deserves wider critical scrutiny and close reading for the theoretical implications it initiates. The novel presents an understanding of what it means to be both a woman and a lover, and it indicates the ways that these two ideas are intertwined. Although it was written in 1976, Lover portrays innovative feminist performances of subject which remain relevant to contemporary feminist readers. The subject this novel envisions is one who is able to enact a seduction that was unavailable to traditional conceptions of self under the dominant framework of Western culture. This article considers how the novel deploys twins and mirrors to complicate the process of mimesis and delves into the symbolism implied by the novel’s references to Medusa, Saint Veronica, and the Hemorrhissa—the biblical woman who was healed of an issue of blood by Christ. In this article, the author takes into account the novel’s negotiation of the fear and horror associated with the female body through postmodern artistic parody and excess. This article finds that Lover presents a version of self that is created by the process of reflection and artistic creation. Through its interaction with the nexuses at which artistic creation and sexuality intersect with both Greek and Christian myths, this novel reassembles a vision of what it means to be a woman

Raios gama na sobrevivência de plantas de maracujazeiro amarelo inoculadas com Fusarium oxysporum f sp. Passiflorae.

A murcha de Fusarium ou fusariose ocorre em diversas regiões produtoras de maracujá amarelo e tem ocasionado grandes danos devido à morte das plantas. A mutagênese associada à seleção in vitro utilizando fitotoxinas possibilita a aplicação de uma pressão de seleção sobre um grande número de propágulos e, assim, pode direcionar a seleção dos mutantes específicos. Neste trabalho, foi analisado o efeito de raios gama sobre a sobrevivência de plantas de maracujazeiro amarelo inoculados com F. oxysporum f. sp. passflorae. Brotações foliares provenientes de segmentos caulinares de P. edulis irradiados a 20Gy foram submetidas a dois ciclos de seleção em meio de cultura suplementado com o filltrado da cultura fúngica (40% e 50% de filtrado). As plantas selecionadas foram inoculadas com a suspensão de conídio em casa de vegetação e após, transferidas para o campo em local com histórico da doença. Ao final da etapa de seleção in vitro, sobreviveram 17,05% das plantas irradiadas e nenhuma planta do tratamento testemunha. A inoculação com a suspensão de conídio não resultou em diferenças significativas na sobrevivência das plantas irradiadas e não irradiadas. No entanto, em condições de campo, foi confirmado o efeito da radiação no aumento da sobrevivência das plantas, sendo verificada a sobrevivência de 77,78% das plantas irradiadas e a morte de todas as plantas do tratamento testemunha

Review of land flow accounting methods and recommendations for further development

Robust land footprint indicators can potentially extend the consumption-based resource use indicator of the German sustainability strategy, which focuses on abiotic resources including fossil fuels, metals, and construction and industrial minerals and decidedly excludes biotic resources. Various approaches exist for quantifying the land embodied in international trade flows and consumption, i.e. the land footprint. These can be classified into a) environmental-economic accounting approaches, applying input-output analysis and tracking supply chains in monetary values, b) physical accounting approaches, using an accounting framework based on data for production, trade and utilization of agricultural and forestry commodities and tracking supply chains in physical units, and c) hybrid accounting, combining elements from both environmental-economic and physical accounting. The results of recent studies vary widely, indicating a lack of robustness and thus hampering their application in policy making. This report provides an in-depth review of the current state of the art in measuring land footprints. We identify differences in available accounting methods and indicate their shortcomings, which are mainly attributable to the product and supply chain coverage and detail, and biases introduced by the use of monetary flows as a proxy for actual physical flows. We offer options and give clear recommendations for the further development of actual and virtual global biomass and land flow accounting methods, particularly highlighting the advantages of hybrid accounting approaches as a framework for the robust and transparent assessment of land footprints associated with global biomass flows

Urban Refugee Education: Strengthening Policies and Practices for Access, Quality, and Inclusion

The number of forcibly displaced people across the globe has increased dramatically in the past two decades, exceeding 65 million in 2016--a level not seen since the period directly following World War II. The image of refugees living together in camps is no longer the norm. Sixty percent of today’s refugees live scattered and embedded across large urban areas. The urbanization of refugees is creating new obstacles for refugee children who find it difficult or impossible to attend school, even though they are entitled by international law to do so. According to the United Nations High Commissioner for Refugees, half the world’s displaced people are children under 18. Half of refugee children are enrolled in primary school, 22 percent in secondary school and only one percent in higher education. Adding to the complications of urbanization, longer conflicts have increased the average worldwide duration of refugee status to 20 years. Millions of refugee children are spending their entire childhoods in exile without ever attending school, despite their right to obtain an education. Despite much public discussion of the global refugee crisis in wealthy, westernized nations, 86 percent of all displaced people reside in the “Global South,” in poor, developing countries, often in countries adjacent to their homelands. That is where we focused our study. This report presents findings of our survey of 190 professionals involved in the delivery of educational services to refugees in 16 countries, including an in-depth studies of refugee education in three cities--Beirut, Lebanon; Nairobi, Kenya; and Quito, Ecuador. The report includes policy recommendations based on our findings

The global cropland footprint of the non-food bioeconomy

A rapidly growing share of global agricultural areas is devoted to the production of biomass for non-food purposes. The derived products include, for example, biofuels, textiles, detergents or cosmetics. Given the far-reaching global implications of an expanding non-food bioeconomy, an assessment of the bioeconomy’s resource use from a footprint perspective is urgently needed. We determine the global cropland footprint of non-food products with a hybrid land flow accounting model combining data from the Food and Agriculture Organization and the multi-regional input-output model EXIOBASE. The globally interlinked model covers all cropland areas used for the production of crop- and animal-based non-food commodities for the years from 1995 to 2010. We analyse global patterns of raw material producers, processers and consumers of bio-based non-food products, with a particular focus on the European Union. Results illustrate that the EU is a major processer and the number one consumer region of non-food cropland, despite being only the fifth largest producing region. Two thirds of the cropland required to satisfy EU non-food consumption are located in other world regions, giving rise to a significant dependency on imported products and to potential impacts on distant ecosystems. With almost 29% in 2010, oilseed production, used to produce, for example, biofuels, detergents and polymers, represents the dominant share in the EU’s non-food cropland footprint. There is also a significant contribution of more traditional non-food biomass uses such as fibre crops (for textiles) and animal hides and skins (for leather products). Our study emphasises the importance of comprehensively assessing the implications of the non-food bioeconomy expansion as envisaged in various policy strategies, such as the Bioeconomy Strategy of the European Commission

Quantifying the land footprint of Germany and the EU using a hybrid accounting model

Footprint analysis reveals the appropriation of land resources from a consumer’s perspective. We here present a novel hybrid land-flow accounting method for the calculation of land footprints, employing a globally consistent top-down approach and combining physical with environmental economic accounting. Physical accounting tracks food products from ‘field to plate’ and non-food from ‘field to industrial use’ using the large harmonized FAO data to track biomass flows and related land use in physical volumes (tons of biomass). Environmental-economic accounting is used to further track non-food commodities in monetary values to final consumption. The hybrid methodology has been applied annually between 1995 and 2010 for 21 regional markets globally and including major economies separately (e.g. USA, China, India). Per capita extents and composition of cropland footprints vary widely across the world. Detailed results for Germany and the EU28 highlight the higher land demand of livestock-based diets compared to crop-based diets, the growing integration in international markets, and the growing importance of the non-food sector since 2000. Today the land footprint of each Germany citizen appropriates on average 2693 m2 cropland (about one half for livestock-based diets, one quarter for crop-based diets and one quarter for non-food products). Additional 1655 m2 of grassland per capita are used for the consumption of ruminant livestock products. Germany is a major and increasing trading partner with current net ‘cropland imports’ of 10.6 Mha. Overall, half of Germany’s 22 Mha cropland footprint relies on domestic cultivation and half on land resources abroad. Albeit large uncertainties in the calculation of grassland footprints, results point towards Germany being a significant net importer of grassland embedded in ruminant livestock products

Evaluation of ILP-based approaches for partitioning into colorful components

The NP-hard Colorful Components problem is a graph partitioning problem on vertex-colored graphs. We identify a new application of Colorful Components in the correction of Wikipedia interlanguage links, and describe and compare three exact and two heuristic approaches. In particular, we devise two ILP formulations, one based on Hitting Set and one based on Clique Partition. Furthermore, we use the recently proposed implicit hitting set framework [Karp, JCSS 2011; Chandrasekaran et al., SODA 2011] to solve Colorful Components. Finally, we study a move-based and a merge-based heuristic for Colorful Components. We can optimally solve Colorful Components for Wikipedia link correction data; while the Clique Partition-based ILP outperforms the other two exact approaches, the implicit hitting set is a simple and competitive alternative. The merge-based heuristic is very accurate and outperforms the move-based one. The above results for Wikipedia data are confirmed by experiments with synthetic instances

Review of the Laguerre-Gauss mode technology research program at Birmingham

Gravitational wave detectors from the advanced generation onwards are expected to be limited in sensitivity by thermal noise of the optics, making the reduction of this noise a key factor in the success of such detectors. A proposed method for reducing the impact of this noise is to use higher-order Laguerre-Gauss (LG) modes for the readout beam, as opposed to the currently used fundamental mode. We present here a synopsis of the research program undertaken by the University of Birmingham into the suitability of LG mode technology for future gravitational wave detectors. This will cover our previous and current work on this topic, from initial simulations and table-top LG mode experiments up to implementation in a prototype scale suspended cavity and high-power laser bench